Combustion chamber for compression ignition internal-combustion engines



July 4, 1950 A. C. HOWARD COMBUSTION CHAMBER FOR COMPRESSION IGNITION INTERNAL-COMBUSTION ENGINES Filed April 3, 1947 Patented July 4, 1950 COMBUSTION. GHAMBER'V FOR COMPRESF; INTERNAL-GOMBUSe SION IGNITION TION' ENGINES.

Arthur Clifford-Howard, Hunslet, Iiee'ds'; England ApplicationAprilB, 1947, .Serial No. '7 39;209 In..Great Britain September 22, ,19451 3 Claims; t

This invention relates to" compression ignition internal'combustion'engines. of'theliquid fuel injection type in which substantially the" wholeof the charge isforced during the compression stroke into'a pocket c'onstituting'the combustion chamber. It is well known that the completeness of combustion in" such an' engine depends" among other'things, upon'the'stat'eof turbulence of the compressed gaseous charge-immediately before and afterfuerinjection" has taken place. With this end in view'various forms of' combustion chambers have been'proposed situatedin the cylinder head wherein the turbulence'has been controlled togive what is known" as a two-way swirl. S'uch'a combustion chamber as proposed; whilst permitting" the desired turbulence has the disadvantageof beingdifiicult to manufacture entailing either a complicated tooling out operation through the restricted access afforded by the throat or'neckwhich, in many-cases is inclined ortangentially disposed;' and to-overcome these diiflculties combustion chambers have been formed as a separate unit comprising one or more parts tofacilitate the accurate formation of the chamber space-therein.- The unit hasbeen inserted into a'through bore in the cylinder'head as a plug fitting. To simplify themachining or tooling of the cylinder head; combustion cham-- bers havebe'en formed therein by means of'a simple parallel-walled bore closed at one end and fully open at the other, formed directly and wholly in the cylinder head from the underside.

The. chief object of thepre'sent invention is to provide a new or improved constructionof forming a combustion chamber which will combine the manufacturing advantages of a simple borewith complete combustion afforded by the turbulence given by the two-way swirl:

According totheinvention the combustion chamber is' affordedby-asimple'bore in thecylinder head leading from the'und'erside thereof, the lower end of said bore beingclosed by means of a.fiame cup. having an oval'or. similar shaped aperture in its base to afford the verticalor main throat leading from the combustion chamber to the cylinder and a secondary aperture to afford a horizontal or turbulent throat. The flame cup will be a loose fit in the bore and the latter will be recessed to accommodate the walls of the flame cup. Said walls may be parallel or tapered throat is afforded" by removing orv cutting: away the area or part ofthe areaiof" the base oflsaid cup which overlaps the cylinder bore and in this connection the undersideof the wall of the flame cup may be. radiusedv over a length equal'lto the width of the aperture.

Alternatively the, throat may beformedby. an elliptical or similar shaped bore leading. through the base of the flame cup which overlaps the cylinder bore.

In order to control the air movement intothe combustion chamber, the underside of the cylinder. head may be grooved or recessed'to match the throat in the flame cup so that when the piston is movingup, the air movement is vertical and runs aroundthe chamber in one direction, but towards the end of the stroke the air movement becomeshori'zontal due to squish effect and the grooved recess directs the air across the bottom ofthe flame cup chamber. This results in the chamber swirl reversing or becomingconfused' with beneficial results to the mixing. of air and injected fuel.

The base ofthe flame cup will be slightly larger than the overall diameter of the Walls to fit in a suitable recess formed in the underside of the cylinder head around the bore into which the flame" cupiis. inserted andan added advantage ofthe flame cup is that the cylinder head gasket and'the' j oining' of the cylinder bore and cylinder liner are protected from the flames and'heat of combustion.

I'n'order that the invention may-be clearly understood and readily carried into effect'the same will now be more fully describedwith reference to and by the aid of the accompanying drawings,- wherein:

Figurel is a part sectional elevation of a flame cup constructed in accordance with the inven tion placed in position in the cylinder head of a, compression ignition engine.

Figure 2 is a diagrammatic plan'view showingthe relationship. of theiflame cup with the cylinder head'an'd bore.

Figures 3, 4 and 5 are an inverted plan, sectional elevation and plan view respectively of a flame cup.

Referring to the drawings, the combustion chamber I is formed in the cylinder head 2 by a bore from the underside thereof within which is fitted a steel flame cup 3, a loose or comfortable fit in said bore and suitably pinned or pegged (not shown) to prevent its rotation therein.

The bore of the combustion chamber i is domeshaped at its upper end 4 and recessed at two places 5 and 6, at 5 to receive the walls 'I of the flame cup 3 and at 6 to receive the peripheral flange 8 on the base 9 of the cup 3. The flame cup constitutes a combustion chamber liner in the head 2 and is made a loose fit in the bore so that it will not readily transfer its heat through the water cooled metal surroundin it. The throat III leading from the combustion chamber I to the cylinder is constituted or formed by an elliptical or similar shaped bore in the base 9 of the flame cup which overlaps the cylinder block I3 in the usual manner. The substantially:

oval shaped aperture II] in the base of the flame cup 3 cuts through the vertical wall to form a secondary aperture II, which constitutes a horizontal turbulent throat. Both apertures I and Il are formed by one and the same opening in the flame cup but in operation the oval shaped aperture I0 which aflords the main throat admits gases moving in a vertical direction while the secondary aperture I'I affording the horizontal turbulent throat, admits gases moving in a, horizontal direction. The area and shape of the throat I 0, viewed in elevation of the cup, may be calculated and formed as desired or expedient although in the preferred form the entrance to the combustion chamber will be an elongated slot substantially as shown and rounded at each end I4 when viewed in plan, whilst the maximum opening of the throat ID will be in a vertical direction e. g. the depth or area which the flame cup 3 overlaps the cylinder wall I I.

In order to afford a lead into the throat for the compressed air when the piston I5 (see Figure 1) is approaching top dead centre, the cylinder head 2 adjacent to the throat I0 is recessed or grooved at It to finally direct the air movement across the bottom of the chamber to set up turbulence by reversing the swirl of the vertically driven air during the earlier portions of the compression stroke of the piston.

The combustion chamber I and recess or groove I6 associated therewith will be arranged in the cylinder head 2 in such a position that valves, valve seats and ports indicated in Figure 2, can be of a maximum efiicient area.

It will be seen that this invention provides a cylinder head having a combustion chamber which is simple and cheap to manufacture which at the same time enables the full advantages of controlled turbulence to be used.

I claim:

1. In an internal combustion engine of the compression ignition type, a combustion chamber having a bore in the cylinder head leading from the underside thereof, the lower end of said bore being closed by a flame cup, said cup having vertical interior walls and having a substantially oval shaped aperture in its base to afford the main vertical throat leading from the combustion chamber to the cylinder, the said aperture extending through the vertical wall of the flame cup to form a secondary aperture in the wall adjacent to the base of said flame cup to provide 4 a horizontal turbulent throat, said secondary aperture leading from the combustion chamber to the cylinder through the vertical main throat, said flame cup havinga loose flt in the bore, and said bore being recessed to accommodate the walls of the flame cup.

2. In an internal combustion engine of the compression ignition type, a combustion chamber having a bore in the cylinder head leading from the underside thereof, the lower end of said bore being closed by a flame cup, said cup having vertical interior walls and having a substantially oval shaped aperture in its base to afford the main vertical throat leading from the combustion chamber to the cylinder through the base of the flame cup which overlaps the cylinder bore, the said aperture extending through the vertical wall of the flame cup to form a secondary aperture in the wall adjacent to the base of said fiame cup to provide a horizontal turbulent throat, said secondary aperture leading from the combustion chamber to the cylinder through the vertical main throat, said flame cup having a loose lit in the bore, and said bore being recessed to accommodate the walls of the flame cup.

3. In an internal combustion engine of the compression ignition type, a combustion chamber having a bore in the cylinder head leading from the underside thereof, the lower end of said bore being closed by a flame cup, said cup having vertical interior walls and having a substantially oval shaped aperture in its base to afiord the main vertical throat leading from the combustion chamber to the cylinder through the base of the flame cup which overlaps the cylinder bore, the said aperture extending through the vertical wall of the flame cup to form a secondary aperture in the wall adjacent to the base of said flame cup to provide a horizontal turbulent throat, said secondary aperture leading from the combustion chamber to the cylinder through the vertical main throat, said horizontal turbulent throat being provided with lead means for the compressed air from the cylinder, said lead means including a-groove formed in the underside of the cylinder head, said flame cup having a loose fit in the bore, and said bore being recessed to accommodate the walls of the flame cup.

ARTHUR CLIFFORD HOWARD.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date 2,112,787 Ricardo Mar. 29, 1938 2,113,711 Ricardo Apr. 12, 1938 2,296,192 Sanders Sept. 15, 1942 FOREIGN PATENTS Number Country Date 415,880 Great Britain Sept. 6, 1934 

